Final answer:
The ACC setting on an ignition switch allows you to operate electrical accessories in your vehicle without turning on the engine.
Step-by-step explanation:
The ACC setting on an ignition switch stands for 'Accessory.' This setting allows you to operate electrical accessories in your vehicle without turning on the engine. When the ignition switch is turned to the ACC position, power is supplied to the radio, lights, and other electrical components, but the engine is not running. This is useful when you want to listen to the radio or charge your phone without draining the battery.